US20040261816A1 - Using bidentate chelators to clean semiconductor wafers - Google Patents
Using bidentate chelators to clean semiconductor wafers Download PDFInfo
- Publication number
- US20040261816A1 US20040261816A1 US10/608,669 US60866903A US2004261816A1 US 20040261816 A1 US20040261816 A1 US 20040261816A1 US 60866903 A US60866903 A US 60866903A US 2004261816 A1 US2004261816 A1 US 2004261816A1
- Authority
- US
- United States
- Prior art keywords
- chelators
- bidentate
- metal complexes
- metal
- chelating ligands
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
- 239000004065 semiconductor Substances 0.000 title claims abstract description 11
- 239000002738 chelating agent Substances 0.000 title claims description 21
- 235000012431 wafers Nutrition 0.000 title abstract description 7
- 229910052751 metal Inorganic materials 0.000 claims abstract description 32
- 239000002184 metal Substances 0.000 claims abstract description 22
- 239000003446 ligand Substances 0.000 claims abstract description 21
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 claims abstract description 12
- 229910002092 carbon dioxide Inorganic materials 0.000 claims abstract description 6
- 239000001569 carbon dioxide Substances 0.000 claims abstract description 6
- 238000000034 method Methods 0.000 claims description 17
- 239000000203 mixture Substances 0.000 claims description 5
- 229910052757 nitrogen Inorganic materials 0.000 claims description 3
- 229910052760 oxygen Inorganic materials 0.000 claims description 3
- 229910052698 phosphorus Inorganic materials 0.000 claims description 3
- 238000004140 cleaning Methods 0.000 claims description 2
- 239000000356 contaminant Substances 0.000 abstract description 4
- 239000008139 complexing agent Substances 0.000 description 6
- 230000015572 biosynthetic process Effects 0.000 description 4
- 230000009920 chelation Effects 0.000 description 4
- YRKCREAYFQTBPV-UHFFFAOYSA-N acetylacetone Chemical compound CC(=O)CC(C)=O YRKCREAYFQTBPV-UHFFFAOYSA-N 0.000 description 2
- 239000012736 aqueous medium Substances 0.000 description 2
- 239000013522 chelant Substances 0.000 description 2
- 239000007788 liquid Substances 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- ROFVEXUMMXZLPA-UHFFFAOYSA-N Bipyridyl Chemical compound N1=CC=CC=C1C1=CC=CC=N1 ROFVEXUMMXZLPA-UHFFFAOYSA-N 0.000 description 1
- XTHFKEDIFFGKHM-UHFFFAOYSA-N Dimethoxyethane Chemical compound COCCOC XTHFKEDIFFGKHM-UHFFFAOYSA-N 0.000 description 1
- PIICEJLVQHRZGT-UHFFFAOYSA-N Ethylenediamine Chemical compound NCCN PIICEJLVQHRZGT-UHFFFAOYSA-N 0.000 description 1
- 125000004429 atom Chemical group 0.000 description 1
- 230000002301 combined effect Effects 0.000 description 1
- 230000003750 conditioning effect Effects 0.000 description 1
- 238000011109 contamination Methods 0.000 description 1
- LEMQFDHLRUSMPZ-UHFFFAOYSA-N ethyl(dimethyl)phosphane Chemical compound CCP(C)C LEMQFDHLRUSMPZ-UHFFFAOYSA-N 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 125000004433 nitrogen atom Chemical group N* 0.000 description 1
- 125000004430 oxygen atom Chemical group O* 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/02041—Cleaning
- H01L21/02043—Cleaning before device manufacture, i.e. Begin-Of-Line process
- H01L21/02052—Wet cleaning only
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B08—CLEANING
- B08B—CLEANING IN GENERAL; PREVENTION OF FOULING IN GENERAL
- B08B7/00—Cleaning by methods not provided for in a single other subclass or a single group in this subclass
- B08B7/0021—Cleaning by methods not provided for in a single other subclass or a single group in this subclass by liquid gases or supercritical fluids
-
- C—CHEMISTRY; METALLURGY
- C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
- C11D—DETERGENT COMPOSITIONS; USE OF SINGLE SUBSTANCES AS DETERGENTS; SOAP OR SOAP-MAKING; RESIN SOAPS; RECOVERY OF GLYCEROL
- C11D7/00—Compositions of detergents based essentially on non-surface-active compounds
- C11D7/22—Organic compounds
- C11D7/26—Organic compounds containing oxygen
- C11D7/263—Ethers
-
- C—CHEMISTRY; METALLURGY
- C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
- C11D—DETERGENT COMPOSITIONS; USE OF SINGLE SUBSTANCES AS DETERGENTS; SOAP OR SOAP-MAKING; RESIN SOAPS; RECOVERY OF GLYCEROL
- C11D7/00—Compositions of detergents based essentially on non-surface-active compounds
- C11D7/22—Organic compounds
- C11D7/26—Organic compounds containing oxygen
- C11D7/264—Aldehydes; Ketones; Acetals or ketals
-
- C—CHEMISTRY; METALLURGY
- C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
- C11D—DETERGENT COMPOSITIONS; USE OF SINGLE SUBSTANCES AS DETERGENTS; SOAP OR SOAP-MAKING; RESIN SOAPS; RECOVERY OF GLYCEROL
- C11D7/00—Compositions of detergents based essentially on non-surface-active compounds
- C11D7/22—Organic compounds
- C11D7/32—Organic compounds containing nitrogen
- C11D7/3209—Amines or imines with one to four nitrogen atoms; Quaternized amines
-
- C—CHEMISTRY; METALLURGY
- C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
- C11D—DETERGENT COMPOSITIONS; USE OF SINGLE SUBSTANCES AS DETERGENTS; SOAP OR SOAP-MAKING; RESIN SOAPS; RECOVERY OF GLYCEROL
- C11D7/00—Compositions of detergents based essentially on non-surface-active compounds
- C11D7/22—Organic compounds
- C11D7/32—Organic compounds containing nitrogen
- C11D7/3281—Heterocyclic compounds
-
- C—CHEMISTRY; METALLURGY
- C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
- C11D—DETERGENT COMPOSITIONS; USE OF SINGLE SUBSTANCES AS DETERGENTS; SOAP OR SOAP-MAKING; RESIN SOAPS; RECOVERY OF GLYCEROL
- C11D7/00—Compositions of detergents based essentially on non-surface-active compounds
- C11D7/22—Organic compounds
- C11D7/36—Organic compounds containing phosphorus
-
- C11D2111/22—
Definitions
- This invention relates generally to cleaning semiconductor wafers prior to the formation of a gate electrode.
- Metals may contaminate semiconductor wafers. Particularly, prior to the formation of the gate electrode, metal contaminants may be present on semiconductor wafers. It is important to remove those contaminants prior to the formation of the gate electrode.
- Dentate refers to the number of coordination sites or sites of attachment between the metal and the chelating ligand.
- a ligand is a molecule that is bonded directly and covalently to the metal center.
- a chelating ligand or chelate forms a ring that includes the metal center.
- the six coordinate or hexadentate chelating ligand must be used in an aqueous liquid mixture. This leads to contamination from the aqueous liquid and also limits the type of molecular surface termination or conditioning that is achievable.
- Volatile, bidentate chemical complexing agents may be used to bind metallic impurities on semiconductor wafers prior to the formation of a gate electrode.
- a six coordinate chelation can be achieved.
- the resulting chelate may be permanently removed under dynamic vacuum or in a stream of supercritical carbon dioxide, to mention two examples.
- bidentate chelation may be a cleaner, more versatile approach compared to using hexadentate chelation by a single, non-volatile, large complexing agent.
- the large complexing agent which is hexadentate
- aqueous media limits the variability of the final molecular surface termination.
- the bidentate chelation of metal atoms or ions that are undesirably adhered to semiconductor surfaces and films may be achieved by volatile complexing agents.
- the resulting hexacoordinate species with three chelators and a metal center may be removed relatively simply because of the volatility of the complexing agents.
- N,N′ chelators such as ethylene diamine and bipyridine. In this case, two nitrogen atoms each can donate a pair of electrons to the metal center, achieving two coordination points.
- O,O′ chelators such as acetylacetone and dimethoxyethane, may be used. Again, these are bidentate chelators which have two oxygen atoms that can form two points of the action.
- P,P′ chelators such as dimethylphosphinoethane, may be used.
- the three chelating ligands may bind to each metal center.
- the result is a hexadentate structure when the combined effect of the three chelating ligands is achieved.
- a chelator specific to that metal may be chosen.
- a chelator may be selected that has a particular affinity for the metal sought to be removed.
- a variety of chelators may be used so that the best combination may be achieved in any given circumstance, in some cases even when the contaminating metal is of unknown chemistry.
Abstract
Bidentate chelating ligands may be utilized to remove metal contaminants in semiconductor wafers. Each metal center may have three chelating ligands attached to it. The resulting complex may be removed as a vapor using a dynamic vacuum or a supercritical carbon dioxide, as two examples.
Description
- This invention relates generally to cleaning semiconductor wafers prior to the formation of a gate electrode.
- Metals may contaminate semiconductor wafers. Particularly, prior to the formation of the gate electrode, metal contaminants may be present on semiconductor wafers. It is important to remove those contaminants prior to the formation of the gate electrode.
- One known technique for removing metal contaminants is to use a hexadentate chelating ligand. Dentate refers to the number of coordination sites or sites of attachment between the metal and the chelating ligand. A ligand is a molecule that is bonded directly and covalently to the metal center. A chelating ligand or chelate forms a ring that includes the metal center. Thus, with a hexadentate chelating ligand, six points of attachment are achieved between the chelating ligand and the metal center.
- The six coordinate or hexadentate chelating ligand must be used in an aqueous liquid mixture. This leads to contamination from the aqueous liquid and also limits the type of molecular surface termination or conditioning that is achievable.
- Thus, there is a need for better ways to clean semiconductor wafers.
- Volatile, bidentate chemical complexing agents may be used to bind metallic impurities on semiconductor wafers prior to the formation of a gate electrode. By using the bidentate chemical complexing agents in a ratio to metal centers of 3 to 1, a six coordinate chelation can be achieved. The resulting chelate may be permanently removed under dynamic vacuum or in a stream of supercritical carbon dioxide, to mention two examples.
- The use of bidentate chelation may be a cleaner, more versatile approach compared to using hexadentate chelation by a single, non-volatile, large complexing agent. Of course, the large complexing agent, which is hexadentate, can only be implemented in an aqueous media. The use of the aqueous media limits the variability of the final molecular surface termination.
- The bidentate chelation of metal atoms or ions that are undesirably adhered to semiconductor surfaces and films may be achieved by volatile complexing agents. Thus, the resulting hexacoordinate species with three chelators and a metal center may be removed relatively simply because of the volatility of the complexing agents.
- Examples of bidentate chelators that are volatile and/or removable in supercritical carbon dioxide include N,N′ chelators, such as ethylene diamine and bipyridine. In this case, two nitrogen atoms each can donate a pair of electrons to the metal center, achieving two coordination points. Similarly, O,O′ chelators, such as acetylacetone and dimethoxyethane, may be used. Again, these are bidentate chelators which have two oxygen atoms that can form two points of the action. As still another example, P,P′ chelators, such as dimethylphosphinoethane, may be used.
- The three chelating ligands may bind to each metal center. The result is a hexadentate structure when the combined effect of the three chelating ligands is achieved.
- When it is desired to remove a particular metal, a chelator specific to that metal may be chosen. In other words, a chelator may be selected that has a particular affinity for the metal sought to be removed. Alternately, a variety of chelators may be used so that the best combination may be achieved in any given circumstance, in some cases even when the contaminating metal is of unknown chemistry.
- While the present invention has been described with respect to a limited number of embodiments, those skilled in the art will appreciate numerous modifications and variations therefrom. It is intended that the appended claims cover all such modifications and variations as fall within the true spirit and scope of this present invention.
Claims (20)
1. A method comprising:
exposing a semiconductor wafer to bidentate chelating ligands; and
removing metal complexes formed by those chelating ligands.
2. The method of claim 1 wherein removing metal complexes includes volatilizing the metal complexes.
3. The method of claim 1 wherein removing the metal complexes includes using supercritical carbon dioxide to remove said complexes.
4. The method of claim 1 including removing said metal complexes as a vapor.
5. The method of claim 1 wherein removing said metal complexes includes removing three bidentate chelating ligands per metal center.
6. A method comprising:
exposing a semiconductor wafer to chelating ligands; and
removing a vapor including the chelating ligands and a metal center.
7. The method of claim 6 wherein removing metal complexes includes volatilizing the metal complexes.
8. The method of claim 6 wherein removing the metal complexes includes using supercritical carbon dioxide to remove said complexes.
9. The method of claim 6 wherein removing said metal complexes includes removing three bidentate chelating ligands per metal center.
10. The method of claim 6 including exposing said wafer to bidentate chelators.
11. The method of claim 10 including exposing the wafer to bidentate O,O′ chelators.
12. The method of claim 10 including exposing said wafer to N,N′ chelators.
13. The method of claim 10 including exposing said wafer to P,P′ chelators.
14. A cleaning composition comprising:
supercritical carbon dioxide; and
bidentate chelating ligands.
15. The composition of claim 14 wherein said ligands are N,N′ chelators.
16. The composition of claim 14 wherein said ligands include O,O′ chelators.
17. The composition of claim 14 wherein said ligands include P,P′ chelators.
18. A method comprising:
volatilizing chelators; and
exposing a semiconductor wafer to said volatilized chelators.
19. The method of claim 18 including volatilizing bidentate chelators.
20. The method of claim 18 including removing metal complexes formed by the chelators.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US10/608,669 US20040261816A1 (en) | 2003-06-27 | 2003-06-27 | Using bidentate chelators to clean semiconductor wafers |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US10/608,669 US20040261816A1 (en) | 2003-06-27 | 2003-06-27 | Using bidentate chelators to clean semiconductor wafers |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| US20040261816A1 true US20040261816A1 (en) | 2004-12-30 |
Family
ID=33540638
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| US10/608,669 Abandoned US20040261816A1 (en) | 2003-06-27 | 2003-06-27 | Using bidentate chelators to clean semiconductor wafers |
Country Status (1)
| Country | Link |
|---|---|
| US (1) | US20040261816A1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE102010017602A1 (en) * | 2010-06-25 | 2011-12-29 | Solarworld Innovations Gmbh | Reducing metal contamination of silicon wafer, comprises contacting the wafer with liquid medium, which comprises compounds that bind the metal contamination in complexes, and applying electrical voltage to the wafer |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20040050406A1 (en) * | 2002-07-17 | 2004-03-18 | Akshey Sehgal | Compositions and method for removing photoresist and/or resist residue at pressures ranging from ambient to supercritical |
| US6767708B1 (en) * | 1994-11-28 | 2004-07-27 | Abbott Laboratories | Stabilized aqueous steroid immunoassay standards |
-
2003
- 2003-06-27 US US10/608,669 patent/US20040261816A1/en not_active Abandoned
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6767708B1 (en) * | 1994-11-28 | 2004-07-27 | Abbott Laboratories | Stabilized aqueous steroid immunoassay standards |
| US20040050406A1 (en) * | 2002-07-17 | 2004-03-18 | Akshey Sehgal | Compositions and method for removing photoresist and/or resist residue at pressures ranging from ambient to supercritical |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE102010017602A1 (en) * | 2010-06-25 | 2011-12-29 | Solarworld Innovations Gmbh | Reducing metal contamination of silicon wafer, comprises contacting the wafer with liquid medium, which comprises compounds that bind the metal contamination in complexes, and applying electrical voltage to the wafer |
| DE102010017602B4 (en) * | 2010-06-25 | 2012-12-27 | Solarworld Innovations Gmbh | Method for reducing the metal contamination of a silicon wafer |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| AS | Assignment |
Owner name: INTEL CORPORATION, CALIFORNIA Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:BRASK, JUSTIN K.;RAMACHANDRARAO, VIJAYAKUMAR S.;REEL/FRAME:014700/0488 Effective date: 20030626 |
|
| STCB | Information on status: application discontinuation |
Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION |